Fuel consumption is generally expressed in a rate (hereinafter referred to as “fuel mileage”). Fuel mileage is provided by dividing an amount of consumed fuel by a traveled distance.
In a certain conventional fuel mileage meter, fuel mileage is calculated in accordance with the following steps:
STEP (hereinafter abbreviated as ST) 101: Determination is made as to whether an ignition is “ON.” In other words, it is determined whether an engine is started. When the answer is YES, the process proceeds to ST102, and when NO, repeats ST101.
ST102: Measurement of distance of travel is started.
ST103: Measurement of the amount of consumed fuel is started.
ST104: It is determined whether the ignition is “OFF.” When the answer is YES, the process proceeds to ST105, and when NO, repeats ST104.
ST105: Fuel mileage is calculated.
ST106: The fuel mileage is displayed.
In the conventional fuel mileage calculation method, measurement of the amount of consumed fuel is performed from the start of the engine for eventual fuel mileage display. Upon start, engines are in an idling state. Inclusion for display of fuel consumption in such an idling state adversely affects the usefulness of fuel mileage display.
Assume that after an engine is started, an idling time of ten minutes is required to wait for someone, and thereafter the vehicle travels along a crowded street. Fuel mileage displayed in such a case is estimated to be smaller than that in the case of traveling along a non-crowded street or an expressway. In certain instances, it should be clarified whether the smaller fuel mileage resulted from the idling or travel along a crowded street.
Thus, demand grows for capability to display fuel mileage reflecting fuel consumption from actual driving and for enhanced usefulness of fuel mileage display.